Radio frequency (RF) electron accelerators are sometimes employed in radiation treatment systems that are used to sterilize medical instruments and materials, pasteurize and disinfest food products, and decontaminate harmful waste. Similarly, RF electron accelerators may be employed in inspection systems for inspecting vehicles, cargo containers, packages, and travelers' luggage. Often, the RF electron accelerators used in such systems comprise linear electron accelerators having an injector for producing electrons that are injected into one or more connected accelerating sections. Electrical fields created within the accelerating sections accelerate the electrons to produce beams of electrons having appropriate energy levels. The electrical fields are, generally, created by power in the form of RF electromagnetic radiation generated by RF generators of the RF electron accelerators. Ferrite insulators are employed between the RF generators and the accelerating section(s) for uncoupling the RF generators and accelerating section(s). Alternatively, ferrite circulators may be employed in lieu of ferrite insulators to uncouple the RF generators and accelerating section(s). Unfortunately, such ferrite uncouplers cause the loss of some of the power produced by the RF generators and, hence, increase the cost of the RF electron accelerators as RF generators capable of producing more power must be utilized to account for the subsequent power losses.
The radiation treatment systems that employ such RF electron accelerators are often configured to direct the electron beams emitted from the accelerators at only one side of objects to be irradiated. In such configurations, the depth of sterilization, pasteurization, disinfestation, or decontamination into an object is, typically, small and the usage efficiency of electron beam power is low. Similarly, in inspection systems that utilize such RF electron accelerators to inspect objects, the data generated from the exposure of the objects to electron beams directed in one direction is sufficient only to produce a single view (i.e., in a single plane) of the objects. Further, in such inspection systems, the generated data is insufficient to discriminate materials of the objects.
In order to overcome the shortcomings of such radiation treatment and inspection systems, two or more RF electron accelerators might be employed in alternative systems to irradiate objects from two or more directions. However, the use of two or more RF electron accelerators would require two or more RF generators, two or more power supplies for the RF generators, and two or more control systems, thereby significantly complicating the alternative systems and increasing their cost.
Therefore, there is a need in the industry for RF electron accelerators and radiation treatment and inspection systems based thereon that irradiate objects from more than one direction and that solve these and other, related and unrelated, difficulties or shortcomings.